We have a lot of experience in JavaScript, writing our services in NodeJS allows developers to transition to the back end without any friction, without having to learn a new language. There is also the option to write services in TypeScript, which adds an expressive type layer. The semi-shared ecosystem between front and back end is nice as well, though specifically NodeJS libraries sometimes suffer in quality, compared to other major languages.

As for why we didn't pick the other languages, most of it comes down to "personal preference" and historically grown code bases, but let's do some post-hoc deduction:

Go is a practical choice, reasonably easy to learn, but until we find performance issues with our NodeJS stack, there is simply no reason to switch. The benefits of using NodeJS so far outweigh those of picking Go. This might change in the future.

PHP is a language we're still using in big parts of our system, and are still sometimes writing new code in. Modern PHP has fixed some of its issues, and probably has the fastest development cycle time, but it suffers around modelling complex asynchronous tasks, and (on a personal note) lack of support for writing in a functional style.

We don't use Python, Elixir or Ruby, mostly because of personal preference and for historic reasons.

Rust, though I personally love and use it in my projects, would require us to specifically hire for that, as the learning curve is quite steep. Its web ecosystem is OK by now (see https://www.arewewebyet.org/), but in my opinion, it is still no where near that of the other web languages. In other words, we are not willing to pay the price for playing this innovation card.

Haskell, as with Rust, I personally adore, but is simply too esoteric for us. There are problem domains where it shines, ours is not one of them.

Context: Writing an open source CLI tool.

Go and Rust over Python: Simple distribution.

With Go and Rust, just build statically compiled binaries and hand them out.

With Python, have people install with "pip install --user" and not finding the binaries :(.

Go and Rust over Python: Startup and runtime performance

Go and Rust over Python: No need to worry about which Python interpreter version is installed on the users' machines.

Go over Rust: Simplicity; Rust's memory management comes at a development / maintenance cost.

Go over Rust: Easier cross compiles from macOS to Linux.

I was thinking about adding a new technology to my current stack (Ruby and JavaScript). But, I want a compiled language, mainly for speed and scalability reasons compared to interpreted languages. I have tried each one (Rust, Java, and Kotlin). I loved them, and I don't know which one can offer me more opportunities for the future (I'm in my first year of software engineering at university).

Which language should I choose?